JPH0341336A - Method and device for analyzing defect of tire through nonuniformity along circumferential direction - Google Patents

Abstract

PURPOSE: To analyze unevenness by fixing a plurality of tires sequentially on a measuring rim, recording data indicative of the circumferential unevenness of each tire at an angular position and then adding the data. CONSTITUTION: A tire 1 is fixed to a measuring rim 10 and turned on a measuring drum 11 turning at a predetermined speed and a stress measuring unit 13 fixed to the shaft 12 of the drum 11 is connected with a pump unit 15. Furthermore, a rotational angle transmitter 1-1 is fixed to the shaft 16 of the rim 10 and connected with the unit 15 which is connected with a computer unit 19. After a part of a tread 9 to be tested is aligned with an index 20 on the rim 10, the rim 10 is turned and the rotational angle is measured by means of the transmitter 17 and a radial stress acting on the drum 11 from the tire 1 is also measured. The rotational angle and the radial stress are operated by the unit 19 and recorded therein and then added to sequential test data thus analyzing the unevenness.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a vehicle tire in which the tread disposed on the outer circumference of each part constituting an automobile tire is firmly bonded to the breaker, belt, or carcass on average. The present invention relates to an analysis method related to uniformity measurement to check for defects in products by analyzing whether there are any non-uniform parts.

[Conventional technology]

Measuring devices such as those mentioned above for analyzing the non-uniformity of automobile tires are actually known, and from the point of view of product management in order to always bring the best tires to the market, such an analysis can be carried out with a high degree of reliability. It is in demand, and a lot of effort is being put into it. In such tire uniformity analysis, the criteria for judgment are particularly radial runout, lateral runout, radial stress variation (radial force variation), and longitudinal stress variation (tractive force variation). Used as a value. Such radial stress changes, lateral stress changes,
Alternatively, in conventional methods for measuring stress changes in the tangential direction, the tire to be measured is mounted on a measuring rim and the measuring operation is carried out.

The tire mounted on the rim is either pressed against a drum with a smooth circumferential surface and rotated by the drum, or the rim itself is rotated and driven.
The axis of the drum is firmly fixed to a suspension stand or the like, and the distance between the axes of the rim and the drum is appropriately determined according to the strength with which the tire is pressed against the drum. When a measuring drum or a measuring rim with a fixed two-axle spacing is driven to rotate in this way, the force with which the automobile tire is pressed against the drum will naturally increase if the circumference of the tire is not completely uniform. This means that the compressive force is not always constant, and changes occur in areas where the bonding is uneven. It is also true that various factors are involved in the causes of such non-uniformity, and although it was possible to confirm non-uniformity in order to indicate tire quality using conventional measurement methods, It was not possible to know what individual measurements should be taken to improve uniformity.

[Problem to be solved by the invention]

However, the main object of the present invention is to improve the above-mentioned method so that the individual effects of uneven locations on tire uniformity can be recognized.

[Means to solve the problem]

According to the present invention, circumferential nonuniformity in the angular position of each tire can be measured by sequentially mounting a plurality of tires on a measurement rim so that the nonuniformity point to be analyzed coincides with the reference position of the measurement rim. The above-mentioned problem can be solved by recording data indicating the tire size and adding the data to analyze the non-uniformity of the tires produced. Similarly, in a measuring rim, a detector integrated therein, and a recording unit for recording the values measured along the circumferential direction of the measuring rim, the rotation angle can be adjusted along the circumferential direction. The above-mentioned problem is solved by a device having an adder for adding up the measured values and a divider for dividing the measured value by the number of tires measured.

[For production]

By using the method according to the invention, it is possible to analyze the influence on tire uniformity individually and easily. Automobile tires have a laminated structure, so unless they are made of a single material, there are always joints between the layers, and if these parts are not properly bonded, various problems can occur. will occur.

For example, in manufacturing tires, if such joints are to be processed perfectly, a series of tires are analyzed one after another using the method of the present invention, even if the rotation angle is always the same. In order to measure stress according to position, it is sufficient to mount the tire on the measuring rim, aligning the markings of the non-uniformity of the joint to be tested with the markings on the measuring rim. As each tire is measured, the analysis values are added up, and while the measured values are added up at the point to be analyzed, non-uniformity in other circumferential areas is calculated statistically over the entire circumference of the tire. Since the information is logically distributed and recorded, the non-uniformity in the required circumferential portion can be relatively analyzed. After measuring a predetermined number of tires, the summed measurements are divided by that number of tires to calculate the influence of non-uniformities due to the joints. Thus, it becomes possible to analyze changes in joints in newly manufactured tires. By comparing the analytical values of the two, it is possible to analyze the actual state of non-uniformity, and as a result, it can be shown which manufacturing process produces better tires.

The invention will now be described in more detail with reference to the accompanying drawings, in which examples are shown.

〔Example〕

Before referring to the analysis method according to the present invention, in order to more clearly show in which parts of the tire the non-uniformities that affect the uniformity of the tire appear, first of all, referring to FIG. Explain the structure.

The tire 1 has thick inner peripheral edges on both sides, which are the portions where the bead wire 2 is wrapped by the chafer 3. The carcass 4 is folded back inside the chafer 3 so as to wrap around the bead wire 2, which extends over the entire tire from one thick part to the other thick part. The carcass 4 is covered with an inner liner 5 on the inside of the tire, and a sidewall 6 is attached to the outside side surface. A strip 7 for protecting the bead wire 2 is applied to the bead wire section, and the carcass 4 is surrounded from the outside by a continuous breaker 8, onto which a tread 9 is welded.

Each of these members that make up a tire must be joined in close contact with each other, but sometimes uneven defects occur along the circumferential direction of the tire, making it difficult to produce a finished product with uniform rigidity. There are things you can't expect.

Now, in order to explain the analysis method according to the present invention, an example will be presented in which, as shown in FIG. 2, it is tested whether the tread 9 really has uniform rigidity.

FIG. 2 schematically shows a measuring device capable of testing stress changes in the radial direction of a tire. During the test, the tire l to be measured is mounted on the measuring rim 10 and rotated at a predetermined rotational speed. Place it on the measuring drum 11 and roll it. The distance between the measuring rim 10 and the drum 11 is appropriately determined so that the tire 1 to be tested is crushed with a predetermined force. By rotating the measuring rim 10 or the measuring drum 11, the tire 1 rolls on the drum 11''. A stress measuring device j3 is mounted on the shaft 12 of the drum 11, which measuring device is connected by a line 14 to the pump unit ]5.

A rotation angle transmitter 17 is also mounted on the shaft 16 of the measuring rim 10 and is also connected to the pump unit 15 via a line 18. The pump unit 15 is further connected to a computer unit 19 and an indicator 20 is provided on the measuring rim 10 to indicate the zero position of the measuring ring.

In the embodiment shown in the drawings, the joint state of the tread 9 is tested, in which case the location of the tread to be tested is placed in line with the indicator 20 of the measuring rim 10. After aligning the test point of the tire with the index in this way, the measuring rim 10 is rotated and its angle is measured by the rotation angle transmitter 17, while at the same time the radial stress exerted on the measuring drum 11 by the tire l is It is measured by a measuring device 13 attached to the shaft of this drum. The two values, namely the radial stress and the angle of rotation ρ, are respectively compared and recorded in the computer unit 15.

Then, the next tire to be tested is mounted on the measuring rim 10 and the above operation is repeated, but the number of tires to be tested continuously is 20, 100 or 1000.
It doesn't matter if it's a book. In any case, the measured values are added and stored one after another in the computer unit 15, and later the overall value is divided by the number of tires tested and the value is outputted by the output unit.

A diagram of the values measured in this way is shown in FIG. The radial stress change (RKS) applied by the tire l is detected by the stress measuring device 13, and the value of this change is entered in the diagram together with the rotation angle ρ. Since the tires 1 to be tested are all mounted on the measuring rim ll according to the index, the tread 9 described above is
The joint 21 contacts the drum 11 when it rotates half a turn, that is, at ρ-I80°. At this location, the radial stress increases as shown by the diadarum, but at other rotational angular positions there is no significant effect. This is because the uneven portions of the tire are statistically distributed over the circumferential direction and are therefore sufficiently far away from the reference tread joint 21.

Even if a series of tires with treads joined by different methods are to be measured, they may also be directly compared and analyzed with each other according to the process described above. In this way, it is possible to quickly determine which method is most advantageous for producing uniform tires.

This method can be used to analyze any non-uniformity in a tire if the non-uniformity is found after vulcanization. If it is not noticeable after vulcanization, it can also be achieved by adding a color index before vulcanization.

〔Effect of the invention〕

1 The advantage of the method and device according to the invention as described above is that it can also be used for the analysis of product defects in any tire, and also for testing tires before they are ready for vulcanization. Concomitantly, the effects of non-circularity in the manufacture of drums or other equipment, the effects of deformation of unvulcanized tire blanks due to lack of proper storage, heating molds, tubes or other The effects of non-circularity are detected as well.

It may be possible to use a stroboscope to synchronize the rotational angle position of the tire location to be analyzed with the measuring machine, but it is possible to use a stroboscope to synchronize the rotation angle position of the tire location to be analyzed with the measuring machine, but it is possible to There is no need to rely on such expensive electronic equipment, as the desired objective can be achieved by manually adjusting the indicators before measurement.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the structure of a passenger car tire; FIG. 2 is an explanatory diagram schematically showing a device for measuring changes in force in the radial direction of the tire (radial force variation) caused by the tread; FIG. 3 is a graph showing the analysis results as a diadem. 1... Tire, 11... Measuring drum, 12.
16... Axis, 13... Stress measuring device, 14.
18... Line, 15... Pump unit, 1
7...Rotation angle transmitter, 18...Line,
19... Computer unit, 20... Index, 2
1...Joint part.

Claims (3)

[Claims] (1) In order to detect circumferential non-uniformity that occurs when treads or similar tire components are laminated together, the tire is mounted on a measuring rim with a rotation angle detector attached to the shaft, and Rotate within an angular range and
In a method of analyzing measurement results of non-uniformity measured at each rotation angle in the circumferential direction, multiple tires are sequentially mounted on a measurement rim so that the non-uniformity point to be analyzed matches the reference position of the measurement rim. An analysis method characterized by recording data indicating circumferential non-uniformity in the angular position of each tire, and adding the data to analyze the non-uniformity of produced tires. (2) An indicator indicating the reference position of the measurement rim and an indicator indicating the uneven location of each tire to be measured are attached in advance, and prior to measurement, these two indicators are arranged in a straight line. The analysis method according to claim 1. (3) In a measuring rim, a detector built into the measuring rim, and a recording unit for recording values measured along the circumferential direction of the measuring rim, the rotation angle measured along the circumferential direction is Laminating a tread or similar tire component, characterized by having an adder for adding matching values and a divider for dividing the measured value by the number of tires measured. In order to detect circumferential non-uniformity that occurs when the tire is rotated over a predetermined angular range by mounting it on a measurement rim with a rotation angle detector attached to the shaft, measurements are taken at each angular position in the circumferential direction. A device for analyzing heterogeneity.